A wrench is a manually operated tool that can be used to tighten or loosen screws or nuts using a rotating action. The wrench is placed or pushed onto a screw head or a nut and has clamping jaws that engage with the screw head or the nut and can transmit a torque exerted with the wrench by the user onto the screw or nut.
A wide range of different wrench designs are known from practice. Wrenches in the form of an open-end wrench are often used for assembling heating and sanitary installations. Screw heads or nuts with a hexagonal profile fit flush into such wrenches and can be turned via a corresponding actuation of the wrench. In order to facilitate simple and reliable handling and actuation of the wrench, it has proved to be advantageous for the wrench to have clamping surfaces on the clamping jaws that are as extensive as possible and that enable a form-fitting engagement with multiple lateral edges of the hexagonal object during a rotational movement.
In order to enable the hexagonal objects to be gripped and pivoted by the wrench even in cramped installation positions, it is expedient for the wrench to have clamping jaws with clamping surfaces that are designed such that the wrench can grip a hexagonal object not only after a rotation through 60°, but also after a rotation of the hexagonal object through 30° in the same direction relative to the hexagonal object and can be used and actuated accordingly for a further rotational movement through 30°.
Several complete rotations of a hexagonal object are usually required in order to fully tighten or loosen the hexagonal object. In the case of individual rotation steps of approximately 30°, the wrench must frequently be removed from the hexagonal object and replaced in order to enable execution of the full tightening process or loosening process of the hexagonal object. In order to facilitate multiple instances of removing and replacing the wrench on the hexagonal object, or to avoid it entirely, various wrenches are known from practice that have a ratchet function for ratcheting increments of 30°. Ratchet wrenches of this kind run free in one direction of rotation and enable renewed gripping of the hexagonal object that has been turned through 30° without the need to loosen and replace the wrench on the hexagonal object. In this case, a first clamping jaw is often mounted pivotably on the wrench handle relative to a second clamping jaw, or on the second clamping jaw. When the ratchet wrench is turned in a tightening direction, both clamping jaws closely abut the hexagonal object and enable a torque to be exerted on the hexagonal object. When the ratchet wrench is turned in a reset direction counter to the tightening direction, the two clamping jaws pivot into a position in which they are spaced apart and enable the ratchet wrench to be turned in a direction of rotation counter to the tightening direction, or in the reset direction relative to the hexagonal object, through 30° or a multiple of 30°, and to then grip the hexagonal object again through another rotational movement of the ratchet wrench in the tightening direction and to turn the hexagonal object in the tightening direction. Such wrenches with a ratchet function are described, for example, in U.S. Pat. No. 4,584,913 or in DE 197 47 536 B4.
In order to place a wrench with a pivotably mounted clamping jaw laterally onto a hexagonal object, it is often necessary to pivot the pivotably mounted clamping jaw wide open and to pivot it into an open receiving position in which the opened clamping jaws have a width that is greater than twice the width of the unopened engagement position where the jaws abut closely. Where the two clamping jaws are intended to abut more than four lateral edges of the hexagonal object in an engagement position in order to ensure that the hexagonal object is gripped such that it is secured against slipping out, an especially widely opened receiving position is required in order to insert the hexagonal object between the two clamping jaws. Widely opened clamping jaws make handling of the wrench more difficult, especially in cramped conditions.
The object of the present invention is therefore to configure a wrench in the form of an open-end wrench for ratcheting increments of 30° such that a hexagonal object can be reliably gripped with the lowest possible space requirements and can be turned with a high level of operating comfort in multiple ratcheting increments of 30° each.